With an ever-growing elderly population, it is becoming increasingly important to monitor physiological correlates associated with age. One major problem associated with age revolves around quantity and quality of sleep. Many commercial devices monitor physiometric nocturnal activity (i.e. actigraphy, EEG, EMG, EOG, respiration, etc.), however, there are no commercial devices available for continuous, non-invasive, near real-time monitoring of chemicals in the blood. The pineal hormone, melatonin, follows a characteristic circadian temporal pattern. Plasma melatonin concentrations are utilized as a correlate indicating sleep, and exogenous application has been utilized in the attempt to improve the quality and quantity of sleep. Contemporary studies on the causal effects of melatonin on sleep require drawing of blood, saliva, or urine, however, each of these techniques require effort on the part of the subject, causing deviation from normal sleep patterns. In this Phase II project, AST proposes to fabricate a continuous, near real-time, non-invasive monitor for blood borne chemicals, including melatonin (as well as a myriad of other biological molecules), obtained during activity or sleep. This device will be amenable to mass screening of the elderly (and pediatric) population, with the potential for actuator regulated exogenous melatonin administration. The device is also applicable to the monitoring of glucose with closed-loop controlled injection of insulin in the attempt to achieve euglycemia at all times.